[dsraven]

if you wanna bring a big power supply into the cab then use a mega fuse near the battery then run wire to your insulated stud under the dash or wherever. the black ground stud is really not required as long as the cab is grounded well. the mega fuse will protect the power supply to the stud, the stud would supply power to individual circuits each protected by it's own smaller fuse through the fuse panel under the dash (usually).
the issue with taking power from the starter is that it is difficult to get a mega fuse close to the starter in order to protect the rest of the big wire that feeds the stud under the dash.